1. Field of the Invention
This invention relates to a projection device of the slit scanning type such as, for example, a copying apparatus, and in particular to a projection device in which the magnification of a projected image can be varied.
2. Description of the Prior Art
Various methods and apparatuses for varying the imaging magnification of the image of the surface of an original projected onto the surface of a photosensitive medium are known. In these apparatuses, during a magnification change, the imaging magnifications in the lengthwise direction and the widthwise direction of a slit scanning the surface of the original are varied so as to be coincident with each other.
In contrast, in recent years, copying apparatuses in which the longitudinal and transverse imaging magnifications differ from each other, or in other words, the imaging magnifications in the lengthwise direction of the slit and the widthwise direction of the slit can be varied so as not to be coincident with each other have been desired for designers or special usages. For such requirement, in a digital copying apparatus wherein the formation of image is accomplished by scanning a photosensitive medium by a laser beam, an image having different imaging magnifications in longitudinal and transverse directions orthogonal to each other can be obtained by electrically processing the conditioned signal of the laser beam.